Portable transponders, employ RFID, Radio Frequency Identification, as the technology used to collect highway tolls, to serve as personal identification for access control, and to provide means for electronic information interchange, such as credit, etc. Passive RFID tags and wireless cards contain chips, (also known as computer chips, microchips, memory chips) which store identification and other information, such as credit card numbers, financial data, etc. Tags may be applied to items to identify the item in much the same way that bar codes are used. Information is retrieved from a tag as well as the wireless cards of the present invention by an RFID base station or reader when the tag or card is scanned with radio waves by the reader. The tags may draw their power to function from the interrogation field supplied by the base (read/write) station.
Such tags, passive tags, are described in U.S. Pat. No. 3,713,148, card Apparatus and System, issued to Cardullo and Parks. In its simplest form the RFID tag or device includes a circuit typically a silicon chip, although more than one chip may be used in the construction of the RFID device. The circuit is generally connected to an antenna. The RFID device or card may take on a variety of forms including that of a tag, a key fob, or a card. A battery may also be employed to extend the range of the device. It is also possible in principle to build devices that function as tags or wireless cards using electrical circuits including only resistors, capacitors and inductors as is well known by those skilled in the art. In some cases the circuit acts as an antenna and thus a separate antenna is not used.
There are also non-electrical circuit memory devices, which are responsive to interrogation, that may be used to construct identification devices contained within cards and tags. Examples of such memory devices include magnetic devices, or wires such as those described in U.S. Pat. No. 5,538,803, “Multibit Tag Using Barkhausen Effect,” resonant structures such as are describe in U.S. Pat. No. 5,563,583, “Multibit Magnetic Radiofrequency Tag Using Micromechanics,” and U.S. Pat. No. 5,581,257, “Radio Frequency Automatic Identification System”.
Large scale retailers and their suppliers are pursuing Radio Frequency Identification, RFID, tagging for supply chain tracking of goods. Demonstrations of RFID for item tagging will lead to point of sale check out and data collection. At the same time, merchants are issuing credit/debit cards that allow a holder to be identified upon entering a place selling merchandise or at the point of sale. This card may be in the form of a credit card that has in it an RFID chip positioned between laminates of the card as well as an antenna attached to the chip, also generally placed within the card laminates. Since the card communicates by a wireless means, it may take other physical forms. For example, Speedpass (see www.speedpass.com) is a wireless RFID credit device that has the form of a small cylinder. It is a key fob carried on a key chain. Likewise, American Express has introduced an RFID credit card, ExpessPay, which is in the form of a rectangular key fob.